Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.
The first amendment doesn't apply.
If two private parties agree via contract to not talk about something then it's a contractual issue not a constitutional issue.
A committee is a group that keeps the minutes and loses hours. -- Milton Berle